<HTML><HEAD><TITLE>set_default_option(+OptionName, +OptionValue)</TITLE>
</HEAD><BODY>[ <A HREF="index.html">library(module_options)</A> | <A HREF="../../index.html">Reference Manual</A> | <A HREF="../../fullindex.html">Alphabetic Index</A> ]
<H1>set_default_option(+OptionName, +OptionValue)</H1>
Permanently set the default value for the given option in the context module
<DL>
<DT><EM>OptionName</EM></DT>
<DD>An atom
</DD>
<DT><EM>OptionValue</EM></DT>
<DD>A valid option term
</DD>
</DL>
<H2>Description</H2>
<P>
    The exact behaviour of this predicate depends on the module from where
    it is invoked: It changes the default value for a named option in the
    context module. The initial default values are defined by the predicate
    default_options/1 in the context module.
</P><P>
    The option name OptionName must be valid according to the predicate
    valid_option_field/2 in the context module, and OptionValue
    must be valid according to valid_option_value/2.
</P>
    
<H3>Modules</H3>
This predicate is sensitive to its module context (tool predicate, see @/2).
<H3>Exceptions</H3>
<DL>
<DT><EM>(4) instantiation fault </EM>
<DD>OptionName or OptionValue are uninstantiated
<DT><EM>(5) type error </EM>
<DD>OptionName is not an atom
<DT><EM>(6) out of range </EM>
<DD>OptionName is not a valid option, or OptionValue is not a valid value in the context module
</DL>
<H2>See Also</H2>
<A HREF="../../lib/module_options/index.html">library(module_options)</A>, <A HREF="../../lib/module_options/get_options-2.html">get_options / 2</A>, <A HREF="../../lib/module_options/print_default_options-1.html">print_default_options / 1</A>
</BODY></HTML>
